Find the width of the rectangle ABCD if the length is 15 cm and the perimeter is 38 cm.

Given:
rectangle ABCD,
BC = 15 centimeters,
P ABCD = 38 centimeters.
Find the width of the rectangle ABCD, that is, AB -?
Solution:
1. Consider the rectangle ABCD. We know that in a rectangle the opposite sides are equal, that is, AB = CD,
AD = BC = 15 centimeters.
2. The perimeter of a rectangle is the sum of the lengths of its sides, that is, P ABCD = AB + BC + CD + AD.
38 = AB + AB + 15 + 15;
38 = AB + AB + 30;
38 = 2 * AB + 30;
2 * AB = 38 – 30;
2 * AB = 8;
AB = 8: 2;
AB = CD = 4 centimeters.
Answer: 4 centimeters.